Enhancing Germination of Seeds of a Multipurpose Tree Species Combretum molle

Abstract

Combretum molle R. Br. ex G. Don (Combretaceae) is a highly valued indigenous multipurpose tree species that has gained considerable attention in recent times due to its importance as a medicinal plant as well as an alternative species for wood and charcoal production. However, we lack adequate information on simple and appropriate methods that could be used to break its distinct seed dormancy to support domestication of wild populations apparently undergoing over exploitation and the negative impacts of deforestation. Eight pre-treatment methods involving complete removal of wing, complete removal of mesocarp, overnight soaking in cold water (24 °C) and partial removal of wing by scorching with fire, and their combinations were tested against the seed dormancy. Of all, the complete removal of mesocarp and overnight soaking in cold water followed with additional soaking in cold water for 24 h took the shortest imbibition (2 days) and germination (7 days) periods, highest germination value (76) and germination energy (80%). Similarly, the same treatment scored significantly (P < 0.05) higher cumulative germination of 72%. To obtain best germination traits, C. molle seeds should be pre-treated by removing the mesocarp and overnight soaking in cold water followed with additional soaking in cold water for 24 h, before sowing. These results have wide implications including supporting domestication and forest landscapes restoration in Tanzania.

Keywords: Domestication; Restoration; Indigenous species; Dormancy; Lesser known species